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Distance geometry and related methods for protein structure determination from NMR data

Published online by Cambridge University Press:  17 March 2009

Werner Braun
Werner Braun
Affiliation:
Institutfür Molekularbiologie u. Biophysik, Eidgenössische Technische Hochschule, Zürich - Hönggerberg, Cff-8093 Zürich, Switzerland
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The method of choice to reveal the conformation of protein molecules in atomic detail has been X-ray single-crystal analysis. Since the first structural analysis of diffraction patterns, computer calculations have been an important tool in these studies (Blundell & Johnson, 1976). As is described by Sheldrick (1985), it has been taken for granted that a necessary first step in the determination of a protein structure would be writing computer programs to fit structure factors. In contrast the combined use of the structural analysis of NMR data and computer calculations has been quite limited. An early attempt of such structural calculations was the quantitative determination of mononucleotide conformations in solution using lanthanide ion shifts (Barry et al. 1971).

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Research Article
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Quarterly Reviews of Biophysics , Volume 19 , Issue 3-4 , May 1987 , pp. 115 - 157
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Copyright © Cambridge University Press 1987

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References

Abe, H., Braun, W., Noguti, T. & Gō, N. (1984). Rapid calculation of first and second derivatives of conformational energy with respect to dihedral angles for proteins. General recurrent equations. Computers & Chemistry 8, 239–247.Google Scholar
Kumar, Anil, Ernst, R. R. & Wüthrich, K. (1980). A two-dimensional nuclear Overhauser enhancement (2D NOE) experiment for the elucidation of complete proton-proton cross-relaxation networks in biological macromolecules. Biochem. biophys. Res. Commun. 95, 1–6.Google Scholar
Kumar, Anil, Wagner, G., Ernst, R. R. & Wüthrich, K. (1981). Buildup rates of the nuclear Overhauser effect measured by two-dimensional proton magnetic resonance spectroscopy: implications for studies of protein conformation. J. Am. chem. Soc. 103,3654–3658.Google Scholar
Armitage, I. M. & Otvos, J. D. (1982). In Biological Magnetic Resonance (ed. Berliner, L. J. and Reuben, J.). New York: Plenum Press.Google Scholar
Arseniev, A. S., Barsukov, I. L., Bystrov, V. F., Lomize, A. L. & Ovchinnikov, Yu. A. (1985). 1H-NMR study of gramicidin A transmembrane ion channel. Headto-head right-handed, single-stranded helices. FEBS Lett. 186, 168–174.Google Scholar
Arseniev, A. S., Kondakov, V. L., Maiorov, V. N. & Bystrov, V. F. (1984). NMR solution spatial structure of short scorpion insectoxin I5A. FEBS Lett. 165, 57–62.Google Scholar
Barry, C. D., North, A. C. T., Glasel, J. A., Williams, R. J. P. & Xavier, A. V. (1971). Quantitative determination of mononucleotide conformations in solution using lanthanide ion shift and broadening NMR probes. Nature 232, 236–245.Google Scholar
Billeter, M., Braun, W. & Wüthrich, K. (1982). Sequential resonance assignments in protein 1H nuclear magnetic resonance spectra. Computation of sterically allowed proton-proton distances in single crystal protein conformations. J. molec. Biol. 155, 321–346.Google Scholar
Billeter, M., Engeli, M. & Wüthrich, K. (1985). Interactive program for investigation of protein structures based on 1H NMR experiments. J. molec. Graph. 3, 79–83.CrossRefGoogle Scholar
Blumenthal, L. M. (1970). Theory and Applications of Distance Geometry. New York: Chelsea.Google Scholar
Blundell, T. L. & Johnson, L. N. (1976). Protein Crystallography, New York: Academic Press.Google Scholar
Bolognesi, M., Gatti, G., Menegatti, E., Guarneri, M., Marquart, M., Papamokos, E. & Huber, R. (1982). Three-dimensional structure of the complex between pancreatic secretary trypsin inhibitor (Kazal-type) and trypsinogen at 1·8 Å resolution. Structure solution, crystallographic refinement and preliminary structural interpretation. J. molec. Biol. 162, 839–868.Google Scholar
Bothner-By, A. A. & Johner, P. E. (1978). Specificity of interproton nuclear Overhauser effects in gramicidin S dissolved in deuterated ethylene glycol. Biophys. J. 24, 779–790.CrossRefGoogle ScholarPubMed
Braun, W. (1983). Representation of short- and long-range handedness in protein structures by signed distance maps. J. molec. Biol. 163, 613–621.CrossRefGoogle Scholar
Braun, W., Bosch, C., Brown, L. R., Go, N. & Wüthrich, K. (1981). Combined use of proton-proton Overhauser enhancements and a distance geometry algorithm for determination of polypeptide conformations. Application to micelle-bound glucagon. Biochim. biophys. Acta 667, 377–396.CrossRefGoogle Scholar
Braun, W. & Gō, N. (1985). Calculation of protein conformations by proton-proton distance constraints. A new efficient algorithm. J. molec. Biol. 186, 611–626.Google Scholar
Braun, W., Wagner, G., W¨orgötter, E., Vasak, M., Kagi, J. H. R. & Wüthrich, K. (1986). Polypeptide fold in the two metal clusters of Metallothionein-2 by nuclear magnetic resonance and distance geometry. J. molec. Biol. 187, 125–129.CrossRefGoogle Scholar
Braun, W., Wider, G., Lee, K. H. & Wüthrich, K. (1983). Conformation of glucagon in a lipid-water interphase by JH nuclear magnetic resonance. J. molec. Biol. 169,921–948.Google Scholar
Braun, W., Yoshioki, S. & Gō, N. (1984). Formulation of static and dynamic conformational analysis of biopolymers systems consisting of two or more molecules. J. Phys. Soc. Japan 53, 3269–3275.CrossRefGoogle Scholar
Brooks, B. R., Bruccoleri, R. E., Olafson, B. D., States, D. J., Swaminathan, S. & Karplus, M. (1983). Charmm: a program for macromolecular energy, minimization and dynamics calculations J. comput. Chem. 4, 187–217.Google Scholar
Brown, L. R., Braun, W., Anil, Kumar & Wüthrich, K. (1982). High resolution nuclear magnetic resonance studies of the conformation and orientation of melittin bound to a lipid-water interface. Biophys. J. 37, 319–328.Google Scholar
Brunger, A. T., Clore, G. M., Gronenborn, A. M. & Karplus, M. (1986).Threedimensional structure of proteins determined by molecular dynamics with interproton distance restraints: Application to crambin. Proc. natn. Acad. Sci. U.S.A. 83, 3801–3805.Google Scholar
Burgess, W. A. & Scheraga, H. A. (1975). Assessment of some problems associated with prediction of the three-dimensional structure of a protein from its amino-acid sequence. Proc. natn. Acad. Sci U.S.A. 72, 1221–1225.CrossRefGoogle ScholarPubMed
Clore, G. M. & Gronenborn, A. M. (1985). Assessment of errors involved in the determination of interproton distance ratios and distances by means of one- and two-dimensional NOE measurements. J. magn. Reson. 61, 158–164.Google Scholar
Glore, G. M., Gronenborn, A. M., Brünger, A. T. & Karplus, M. (1985). Solution conformation of a heptadecapeptide comprising the DNA binding helix F of the cyclic AMP receptor protein of Escherichia coli. Combined use of 1H nuclear magnetic resonance and restrained molecular dynamics. J. molec. Biol. 186, 435–455.Google Scholar
Crippen, G. M. (1977). A novel approach to the calculation of conformation: Distance Geometry. J. comp. Phys. 26, 449–452.Google Scholar
Crippen, G. M. (1981). Distance geometry and conformational calculations. In Chemometrics Research Studies Series, vol. 1 (ed. Bawden, D.). New York: Research Studies Press.Google Scholar
Crippen, G. M. & Havel, T. F. (1978). Stable calculations of coordinates from distance information. Acta Crystallogr. A 34, 282–284.Google Scholar
Crippen, G. M., Oppenheimer, N. & Conolly, M. (1981). Distance geometry analysis of the N.M.R. evidence on the solution conformation of bleomycin. Int. J. Peptide Protein Res. 17, 156–169.Google Scholar
De Marco, A., Llinas, M. & Wüthrich, K. (1978 a). Analysis of the 1H-NMR spectra of ferrichrome peptides. I. The non-amide protons. Biopolymers 17, 617–636.CrossRefGoogle Scholar
De Marco, A., Llinas, M. & Wüthrich, K. (1978 b). Analysis of the 1H-NMR spectra of ferrichrome peptides. II. The amide resonances. Biopolymers 17, 637–650.CrossRefGoogle Scholar
Diamond, R. (1974). Real-space refinement of the structure of hen egg-white lysozyme. J. molec. Biol. 82, 371–391.CrossRefGoogle ScholarPubMed
Dubs, A., Wagner, G. & Wüthrich, K. (1979). Individual assignments of amide proton resonances in the proton NMR spectrum of the basic pancreatic trypsin inhibitor. Biochim. biophys. Acta 577, 177–194.Google Scholar
Fletcher, R. (1980). Practical Methods of Optimization: Unconstrained Optimization. New York: Wiley.Google Scholar
Frey, M. H., Wagner, G., Vasak, M., Sorensen, O. W., Neuhaus, D., W¨orgötter, E., Kagi, J. H. R., Ernst, R. R., Wüthrich, K. (1985). Polypeptide-metal cluster connectivities in metallothionein 2 by novel 1H–113Cd heteronuclear two-dimensional NMR experiments. J. Am. chem. Soc. 107, 6847–6851.Google Scholar
Furey, W. F., Robbins, A. H., Clancy, L. L., Winge, D. R., Wang, B. C. & Stout, C. D. (1986). Crystal structure of Cd, Zn metallothionein. Science 231, 704–710.Google Scholar
Gō, N., Noguti, T. & Nishikawa, T. (1983). Dynamics of a small globular protein in terms of low-frequency vibrational modes. Proc. natn. Acad. Sci. U.S.A. 80, 3696–3700.Google Scholar
Gō, N. & Scheraga, H. A. (1978). Calculation of the conformation of cyclohexaglycyl. 2. Application of a Monte-Carlo method. Macromolecules II, 552–559.CrossRefGoogle Scholar
Havel, T. F., Crippen, G. M. & Kuntz, I. D. (1979). Effects of distance constraints on macromolecular conformation. II Simulation of experimental results and theoretical predictions. Biopolymers 18, 73–81.Google Scholar
Havel, T. F., Kuntz, I. W. & Crippen, G. M. (1983). The theory and practice of distance geometry. Bull. math. Biol. 45, 665–720.CrossRefGoogle Scholar
Havel, T. F. & Wüthrich, K. (1984). A distance geometry program for determining the structures of small proteins and other macromolecules from nuclear magnetic resonance measurements of intramolecular 1H–1H proximities in solution. Bull. math. Biol. 46, 673–698.Google Scholar
Havel, T. F. & Wüthrich, K. (1985). An evaluation of the combined use of nuclear magnetic resonance and distance geometry for the determination of protein conformations in solution. J. molec. Biol. 182, 281–294.CrossRefGoogle ScholarPubMed
Jardetztky, O., Lane, A., Lefevre, J.-F., Lichtarge, O., Hayes-Roth, B. & Buchanan, B. (1986). In NMR in the Life Sciences, New York: Plenum Press.Google Scholar
Jardetzky, O. & Roberts, G. C. K. (1981). NMR in Molecular Biology, New York: Academic Press.Google Scholar
Jeener, J., Meier, B. H., Bachmann, P. & Ernst, R. R. (1979). Investigation of exchange processes by two-dimensional NMR spectroscopy. J. chem. Phys. 71, 4546–4553.CrossRefGoogle Scholar
Jones, C. R., Sikakana, C. T., Hehir, S., Kuo, M. & Gibbons, W. A. (1978). The quantitation of nuclear Overhauser effect methods for total conformational analysis of peptides in solution. Application to gramicidin S. Biophys. J. 24, 815–832.CrossRefGoogle ScholarPubMed
Kägi, J. H. R. & Nordberg, M. (1979). Metallothionein, Basel: Birkhauser-Verlag.CrossRefGoogle ScholarPubMed
Kaptein, R., Zuiderweg, E. R. P., Scheek, R. M., Boelens, R. & Van Gunsteren, W. F. (1985). A protein structure from nuclear magnetic resonance data. Lac repressor headpiece. J. molec. Biol. 182, 179–182.Google Scholar
Karplus, M. (1959). Contact electron-spin coupling of nuclear magnetic moments. J. Chem. Phys. 30, 11–15.Google Scholar
Karplus, M. (1963). Vicinal proton coupling in nuclear magnetic resonance. J. Am. chem. Soc. 85, 2870–2871.CrossRefGoogle Scholar
Karplus, M. & McCammon, J. A. (1981). The internal dynamics of globular proteins. C.R.C. Crit. Rev. Biochem. 9, 293–349.Google Scholar
Keepers, J. W. & James, T. L. (1984). A theoretical study of distance determinations from NMR. Two-dimensional nuclear Overhauser effect spectra. J. magn. Reson. 57, 404–426.Google Scholar
Kline, A. D., Braun, W. & Wüthrich, K. (1986). Studies by 1H nuclear magnetic resonance and distance geometry of the solution conformation of tendamistat an α-amylase inhibitor. J. molec. Biol. 189, 377–382.Google Scholar
Kobayashi, Y., Ohkubo, T., Kyogoku, Y., Nishiuchi, Y., Sakak-Ibara, S., Braun, W. & Gō, N. (1985). Conformational analysis of conotoxin and its analogue by NMR measurements and distance geometry algorithm. Proc gth Am. Peptide Symp. (ed. Kopple, K. D. and Deber, C. M.). Pierce Chem. Comp., Rockford (in the Press.)Google Scholar
Krishna, N. R., Agresti, D. G., Glickson, J. D. & Walter, R. (1978). Solution conformation of peptides by the intramolecular nuclear Overhauser effect experiment. Study of Valinomycin-K. Biophys. J. 24, 791–814.Google Scholar
Leach, S. J., Némethy, G. & Scheraga, H. A. (1977). Use of proton nuclear Overhauser effects for the determination of the conformations of amino acid residues in oligopeptides. Biochem. biophys. Res. Commun. 75, 207–215.CrossRefGoogle ScholarPubMed
Levitt, M. (1982). Protein conformation, dynamics, and folding by computer simulation. Ann. Rev. Biophys. Bioeng. 11, 251–271.Google Scholar
Levitt, M. (1983). Protein folding by restrained energy minimization and molecular dynamics. J. molec. Biol. 170, 723–764.CrossRefGoogle ScholarPubMed
Levitt, M., Sander, C. & Stern, P. S. (1985). Protein normal-mode dynamics: trypsin inhibitor, crambin, ribonuclease and lysozyme. J. molec. Biol. 181, 423–447.Google Scholar
Live, D., Armitage, I. M., Dalgarno, D. C. & Cowburn, D. (1985). Two-dimensional 1H–113Cd chemical shift correlation maps by 1H-detected multiple quantum NMR in metal complexes and metalloproteins. J. Am. chem. Soc. 107, 1775–1777.Google Scholar
Macura, S. & Ernst, R. R. (1980). Elucidation of cross relaxation in liquids by two-dimensional N.M.R. spectroscopy. Mol. Phys. 41, 95–117.Google Scholar
Marion, D., Genest, M., Caille, A., Peypoux, F., Michel, G. & Ptak, M. (1986). Conformational study of bacterial lipopeptides: refinement of the structure of iturin A in solution by two-dimensional 1H-NMR and energy calculations. Biopolymers 25, 153–170.Google Scholar
Markley, J. L., Westler, W. M., Chan, T.-M., Kojiro, C. L. & Ulrich, E. L. (1984). Two-dimensional NMR approaches to the study of protein structure and function. Proc. 74th Ann. Meeting Am. Soc. Biol. Chem., San Francisco 43, 2648–2656.Google Scholar
McLachlan, A. D. (1979). Gene duplications in the structural evolution of chymotrypsin. J. molec. Biol. 128, 49–79.Google Scholar
Meirovitch, H. & Scheraga, H. A. (1981). Introduction of short-range restrictions in a protein-folding algorithm involving a long-range geometrical restriction and short-, medium- and long-range interactions. Proc. natn. Acad. Sci. U.S.A. 78, 6584–6587.CrossRefGoogle Scholar
Momany, F. A., McGuire, R. F., Burgess, A. W. & Scheraga, H. A. (1975). Energy parameters in polypeptides. VII. Geometric parameters, partial atomic charges, nonbonded interactions, hydrogen bond interactions, and intrinsic torsional potentials for the naturally occurring amino acids. J. phys. Chem. 79, 2361–2381.Google Scholar
Nagayama, K. & Wüthrich, K. (1981). Structural interpretation of vicinal protonproton coupling constants 3J HαHβ in the basic pancreatic trypsin inhibitor measured by two-dimensional J-resolved NMR spectroscopy. Eur. J. Biochem. 115, 653–657.Google Scholar
Nemethy, G. & Scheraga, H. A. (1977). Protein folding. Q. Rev. Biophys. 10, 239–352.Google Scholar
Neuhaus, D., Wagner, G., Vašak, M., Kagi, J. H. R. & Wüthrich, K. (1985). Systematic application of high-resolution, phase-sensitive two-dimensional 1H-NMR techniques for the identification of the amino-acid-proton spin systems in proteins. Eur. J. Biochem. 151, 257–273.Google Scholar
Noggle, J. H. & Schirmer, R. E. (1971). The Nuclear Overhauser Effect. New York: Academic Press.Google Scholar
Noguti, T. & Gō, N. (1983). A method of rapid calculation of a second derivative matrix of conformational energy for large molecules. J. Phys. Soc. (Japan) 52, 3685–3690.Google Scholar
Ohkubo, T., Kobayashi, Y., Shimonishi, Y., Kyogoku, Y., Braun, W. & Gō, N. (1986). A conformational study of polypeptides in solution by 1H-NMR and distance geometry. Biopolymers 25 (S), 123–134.Google Scholar
Olejniczak, E. T., Dobson, C. M., Karplus, M. & Levy, R. M. (1984). Motional averaging of proton nuclear Overhauser effects in proteins. Predictions from a molecular dynamics simulation of lysozyme. J. Am. Chem. Soc. 106, 1923–1930.Google Scholar
Olejniczak, E. T., Gampe, R. T. & Fesik, S. W. (1986). Accounting for spin diffusion in the analysis of 2D NOE data. J. magn. Reson. 67, 28–41.Google Scholar
Ooi, T., Nishikawa, K., Oobatake, M. & Scheraga, H. A. (1978). Flexibility of bovine pancreatic trypsin inhibitor. Biochim. biophys. Acta 536, 390–405.Google Scholar
Otvos, J. D., Engeseth, H. R. & Wehrli, S. (1985). Multiple-quantum 113Cd–1H correlation spectroscopy as a probe of metal coordination environments in metalloproteins J. magn. Reson. 61, 579–584.Google Scholar
Papamokos, E., Weber, E., Bode, W., Huber, R., Empie, M. W., Kato, I. & Laskowski, M. (1982). Crystallographic refinement of Japanese quail ovomucoid, a Kazal-type inhibitor, and model building studies of complexes with serine proteases. J. molec. Biol. 158, 515–537.CrossRefGoogle ScholarPubMed
Pardi, A., Billeter, M. & Wüthrich, K. (1984). Calibration of the angular dependence of the amide proton-Ca proton coupling constants, 3JHNα, in a globular protein. J. molec. Biol. 180, 741–751.Google Scholar
Pflugrath, J. W., Wiegand, G., Huber, & Vertesy, L. (1986). Crystal structure determination, refinement and the molecular model of the α-amylase inhibitor Hoe-467A. J. molec. Biol. 189, 383–386.Google Scholar
Pottle, C., Pottle, M. S., Tuttle, R. W., Kinch, R. J. & Scheraga, H. A. (1980). Conformational analysis of proteins: algorithms and data structures for array processing. J. comp. Chem. 1, 46–58.Google Scholar
Purisima, E. O. & Scheraga, H. A. (1986). An approach to the multiple minima problem by relaxing dimensionality. Proc. natn. Acad. Sci. U.S.A. 83, 2782–2786.Google Scholar
Richards, F. M. (1974). The interpretation of protein structures: total volume, group volume distribution and packing density. J. molec. Biol. 82, 1–14.Google Scholar
Richardson, J. S. (1981). The anatomy and taxonomy of protein structure. Adv. Prot. Chem. 34, 167–335.Google ScholarPubMed
Sasaki, K., Dockerill, S., Adamiak, D. A., Tickle, I. J. & Blundell, T. (1975). X-ray analysis of glucagon and its relationship to receptor binding. Nature (Lond.) 257, 751–757.CrossRefGoogle ScholarPubMed
Saxe, J. B. (1979). Embeddability of weighted graphs in k-space is strongly NP-hard. Proc. 17th Allerton Conf. Communication, Control and Computing, pp. 480–489.Google Scholar
Schlitter, J. (1986). Calculation of coordinates from incomplete and incorrect distance data. J. appl. Math. Phys. (in the Press).Google Scholar
Schmidt, P. G. & Kuntz, I. D. (1984). Distance measurements in spin-labeled lysozyme. Biochemistry 23, 4261–4266.Google Scholar
Senn, H., Billeter, M. & Wüthrich, K. (1984). The spatial structure of the axially bound methionine in solution conformations of horse ferrocytochrome c and Pseudomonas aeruginosa ferrocytochrome c 551 by 1H NMR. Eur. biophys. J. 11, 3–15.Google Scholar
Sheldrick, G. M. (1985). Computing aspects of crystal structure determination. J. molec. Struct. 130, 9–16.CrossRefGoogle Scholar
Sippl, M. J. & Scheraga, H. A. (1985). Solution of the embedding problem and decomposition of symmetric matrices. Proc. natn. Acad. Sci. U.S.A. 82, 2197–2201.Google Scholar
Sippl, M. J. & Scheraga, H. A. (1986). Caley-Menger coordinates. Proc. natn. Acad. Sci. U.S.A. 83, 2283–2287.CrossRefGoogle ScholarPubMed
Smith, G. M. & Veber, D. F. (1986). Computer-aided, systematic search of peptide conformations constrained by NMR data. Biochem. Biophys. Res. Comm. 134, 907–914.Google Scholar
Van De Ven, F. J. M., De Bruin, S. H. & Hilbers, C. W. (1984). Two-dimensional Fourier transform 1H NMR studies of ribosomal protein E-L30. FEBS Letters 169, 107–111.Google Scholar
Van Gunsteren, W. F. & Berendsen, H. J. C. (1982). Molecular dynamics: perspective for complex systems. Biochem. Soc. Trans. 10, 301–305.Google Scholar
Vašak, M. & Kägi, J. H. R. (1983). In Metal Ions in Biological Systems (Sigel, H. ed.) Marcel Dekker, New York.Google Scholar
Vertesy, L., Oeding, V., Bender, R., Zepf, K. & Nesemann, G. (1984). Tendamistat (HOE 467), a tight-binding α-amylase inhibitor from Streptomyces tendae 4158. Eur. J. Biochem. 141, 505–512.Google Scholar
Wagner, G., Braun, W., Havel, T. F., Schaumann, T., Gō, N. & Wüthrich, K. (1987). Protein structures in solution by nuclear magnetic resonance and distance geometry: the polypeptide fold of the basic pancreatic trypsin inhibitor determined using two different algorithms, Disgeo and Disman. (Submitted.)Google Scholar
Wagner, G., Frey, M. H., Neuhaus, D., W¨orgötter, E., Braun, W., Vašak, M., Kägi, J. H. R. & Wüthrich, K. (1985). In Proc. 2nd Int. meeting on Metallothionein, Birkhauser Verlag, Basel.Google Scholar
Wagner, G. & Wüthrich, K. (1979). Truncated driven nuclear Overhauser effect (TOE). A new technique for studies of selective 1H–1H Overhauser effects in the presence of spin diffusion. J. magn. Reson. 33, 675–680.Google Scholar
Wagner, G. & Wüthrich, K. (1982 a). Sequential resonance assignments in protein 1H NMR spectra: basic pancreatic trypsin inhibitor. J. molec. Biol. 155, 347–366.Google Scholar
Wagner, G. & Wüthrich, K. (1982 6). Amide proton exchange and surface conformation of the basic pancreatic trypsin inhibitor in solution. Studies with two-dimensional nuclear magnetic resonance. J. molec. Biol. 160, 343–361.Google Scholar
Wako, H. & Scheraga, H. A. (1981). On the use of distance constraints to fold a protein. Macromolecules 14, 961–969.Google Scholar
Walter, J. & Huber, R. (1983). Pancreatic trypsin inhibitor. A new crystal form and its analysis. J. molec. biol. 167, 911–917.Google Scholar
Weber, P. L., Wemmer, D. E. & Reid, B. R. (1985). 1H NMR studies of the A Cro repressor. 2. Sequential resonance assignments of the 1H NMR spectrum. Biochemistry, 24 4553–4562.Google Scholar
Williamson, M. P., Havel, T. F. & Wüthrich, K. (1985). Solution conformation of proteinase inhibitor IIA from bull seminal plasma by 1H nuclear magnetic resonance and distance geometry. J. molec. Biol. 182, 295–315.Google Scholar
Wüthrich, K. (1986). NMR of Proteins and Nucleid Acids. New York: Wiley.Google Scholar
Wüthrich, K., Billeter, M. & Braun, W. (1983). Pseudo-structures for the 20 common amino acids for use in studies of protein conformations by measurements of intramolecular proton-proton distance constraints with nuclear magnetic resonance. J. molec. Biol. 169, 949–961.Google Scholar
Wüthrich, K., Billeter, M. & Braun, W. (1984). Polypeptide secondary structure determination by nuclear magnetic resonance observation of short proton-proton distances. J. molec. Biol. 180, 715–740.Google Scholar
Wüthrich, K., Wider, G., Wagner, G., Braun, W. (1982). Sequential resonance Assignments as a basis for determination of spatial protein structures by high resolution proton nuclear magnetic resonance. J. molec. Biol. 155, 311–319.Google Scholar
Zuiderweg, E. R. P., Billeter, M., Boelens, R., Scheek, R. M., Wüthrich, K. & Kaptein, R. (1984). Spatial arrangement of the three a helices in the solution conformation of E. colt lac repressor DNA-binding domain. FEBS Lett. 174, 243–247.Google Scholar
Zuiderweg, E. R. P., Kaptein, R. & Wüthrich, K. (1983). Secondary structure of the lac repressor DNA-binding domain by two-dimensional XH nuclear magnetic resonance in solution. Proc. natn. Acad. Sci. U.S.A. 80, 5837–5841.Google Scholar